Orbital and surface observations demonstrate that aeolian activity is occurring on Mars. Here we report the aeolian changes observed in situ by NASA's InSight lander during the first 400 sols of operations. Aeolian changes include creep of grains with diameters of up to 3 mm, dust removal, dark trails left by passing vortices and possible saltation. InSight has observed such changes by using, for the first time, simultaneous imaging and continuous, high-frequency meteorological, seismological, and magnetic measurements. We show that this multi-instrument combination constrains both the timing, and specific atmospheric conditions during which, aeolian changes occur. The observed changes are infrequent and episodic, consistently occur between noon and 3 pm, and are systematically associated with the passage of convective vortices. The sudden onset of peak vortex wind speeds promotes particle motion during sequences of enhanced vortex activity and stronger ambient winds. Aeolian changes are correlated with excursions in ground acceleration and magnetic field strength, suggesting vortex-induced ground deformation and charged-particle motion.

Geochemical constraints on mantle temperature indicate a regular decrease by around 250 K since 3 Ga. However models of Earth’s cooling that rely on scaling laws for thermal convection without strong plates are facing a thermal runaway backwards in time, due to the power-law dependence of heat loss on temperature. To explore the effect of surface dynamics on Earth’s cooling rate, we build a 2D temperature-dependent model of plate tectonics that relies on a force balance for each plate and on Earth-like parameterized behaviors for the motion, creation and disappearance of plate boundaries. While our model predicts the expected thermal runaway if plate boundaries are fixed, we obtain an average cooling rate consistent with geochemical estimates if the geometry of plate tectonics evolves through time. For a warmer mantle in the past, plates are faster but also longer (and less numerous) so that the average seafloor age and resulting heat flux always remain moderate. The predicted increase in the number of plates forwards in time is in good agreement with recent plate reconstructions over the last 400 Myr. Our model also yields plate speed and subduction area flux consistent with these reconstructions. We finally compare the effect of parameters controlling mantle viscosity and individual plate speeds to the effect of localized surface processes, such as oceanization and subduction initiation. We infer that studies of Earth’s thermal history should focus on surface processes as they appear to be key control parameters.

Questions regarding the development of folds and their interactions with the seismic faults within thrust systems remain unanswered. However, estimating fault slip and earthquake hazards using surface observations and kinematic models of folding requires an understanding of how the shortening is accommodated during the different phases of the earthquake cycle. Here, we construct 16-years of InSAR time series across the North Qaidam thrust system (NE Tibet), where three Mw 6.3 earthquakes occurred along basement faults underlying shortened folded sediments. The analysis reveals spatio-temporal changes of post-seismic surface displacement rates and patterns, which continue more than ten years after the seismic events. The decomposition of the Sentinel-1 ascending and descending LOS velocities into vertical and shortening post-seismic components indicates that long-term transient uplift and shortening coincide spatially with young anticlines observed in the geomorphology and cannot simply be explained by elastic slip along dislocations. These findings provide evidences for fold buckling during the post-earthquake phase and highlight the contribution of distributed aseismic deformation to the growth of topography.

The dynamics and evolution of deltas and their channel networks involve interactions between many factors, including water and sediment discharge and cohesion from fine sediment and vegetation. These interactions are likely to affect how much vegetation influences deltas, because increasing sediment discharge increases aggradation rates on the delta and may result in sediment transport processes happening on timescales that are faster than those for vegetation growth. We explore how varying water and sediment discharge changes vegetation’s effect on delta evolution. We propose two new insights into delta evolution under different discharge conditions. First, without vegetation, we observe a regime shift in avulsion dynamics with increasing water discharge, from a few active channels supplemented by overbank flow and undergoing episodic avulsion (with low discharge) to many active channels experiencing frequent partial avulsions (with high discharge). Second, with vegetation, increased aggradation results in more frequent switching of the dominant channels with increased sediment discharge, but also prevents vegetation from establishing in non-dominant channels resulting in more frequent channel reoccupation and therefore greater stability in channel network planform. These insights have important implications for understanding the distribution of water, sediment, and nutrients on deltas in the face of future changes in climate, human modifications of fluxes of sediment and water to the coast, and especially for restored or engineered deltas with controlled water or sediment discharges.

Linear elastic fracture mechanics (LEFM) suggests that short-lived flow accelerations, such as the one observed in the 2006 Byrd Glacier, East Antarctica, subglacial flooding event, can initiate abnormally large basal crevasses at the grounding line. Airborne radar measurements acquired in 2011 reveal hundreds of basal crevasses ranging in height ~40—335 m. Particle tracking results show that the formation of the largest basal crevasse occurred at the grounding line during the 2006 flooding event. Very large basal crevasses form distinctive surface depressions directly overhead, which are observed along the Byrd Glacier flowline to the terminus of the Ross Ice Shelf. By using these surface depressions as proxy for abnormally large basal crevasses, we create a timeline of past subglacial flooding events on Byrd Glacier. Understanding the frequency of flooding events and their effect on glacier dynamics will help inform subglacial hydrology models and models of ice sheet stability.

Mountainous landscape evolution under tropical and alpine environments is mainly dictated by climatic forcing which influences underlying mechanisms of geomorphic transport (e.g., soil formation, river dynamics, slope stability and mass wasting). The time scale over which this influence acts ranges from seasonal to decennial time span. On the seasonal time scale, for accessible locations and when manpower is available, direct observations and field survey are the most useful and standard approaches. While very limited studies have been focused on the the decennial and century scale due to observational constrains. Here, we present an open and reproducible pipeline based on historical aerial images (up to 70yrs time span) that includes sensor calibration, dense matching and elevation reconstruction over two areas of interest that represent pristine examples for tropical and alpine environments: The Rempart Canyon in Reunion Island, and the Bossons glacier in the French Alps share a limited accessibility (in time and space) that can be overcome only from remote-sensing. We reach unprecedented resolution: the aero-triangulation falls at sub-metric scale based on ground truth, which is comparable to the initial images spatial sampling. This provides elevation time series with a better resolution to most recent satellite images such as Pleiades. In the case of the Rempart Canyon, we identified and quantified the results of 2 landslides that occurred in 1965 and 2001, and characterized the landslides dynamics. As for the alpine case, we highlight the effect of the temperature plateau occurred during 1939-1970 in Europe before the well known accelerated retreat during the post-industrial period. In both cases, we emphasize the strong effect of extreme events over multi-decennial to century time-scales.

A simple statistical test is used in cyclostratigraphy to discover candidate orbital frequencies in power spectra of climate proxy data-series. In published studies at least, this test never fails to find multiple frequencies, at high levels of statistical significance (e.g. p<0.01). However, the same method finds similarly high statistical significance at similar numbers of frequencies in random, simulated datasets. The problem lies with the standardised application of the test, which is linked to MTM spectral analysis in a one-step procedure that is readily accessible through specialist software packages. This procedure presents confidence limits as if they were context-free, but statistical tests are necessarily tied to specific (null) hypotheses. The test as used in cyclostratigraphy is calibrated for application at a single frequency, but it is routinely used as if applicable at all frequencies, a practice that invokes the statistical multiple comparisons problem and which largely explains the inadvertent conversion of noise to signal when applied to random datasets. This general problem is addressed here with reference to a specific recently published case.

Abstract Gas relative permeability, krg, is a key parameter to determine gas production in unconventional reservoirs. Several theoretical approaches were proposed to study gas relative permeability in tight and ultra-tight porous rocks. Some models are based on a “bundle of capillary tubes” concept. Some others were developed based upon a combination of universal scaling laws from percolation theory and the effective-medium approximation (EMA). Although applications from the EMA have been successfully used to estimate single-phase permeability in permeable media (Ghanbarian et al., 2017; Ghanbarian and Javadpour, 2017), non-universal scaling from the EMA has never been invoked to model gas relative permeability in tight and/or ultra-tight porous rocks. In this study, it was assumed that pore-throat sizes follow the log-normal distribution. It was further assumed that gas transport in shales is mainly controlled by molecular and hydraulic flow, two mechanisms contributing in parallel. Using the EMA, effective pore-throat radii, effective conductances, and gas relative permeabilities were determined at various gas saturations. Comparison with three-dimensional pore-network simulations showed that the proposed krg model estimated gas relative permeability accurately. We also compared our model with experimental data reported in Yassin et al. (2016) including three Montney tight gas siltstone samples from the Western Canadian Sedimentary Basin. Results showed that our model estimated krg reasonably well, although it slightly overestimated krg. This might be because the fitted log-normal probability density function underestimated the probability of small pore-throat sizes. References Ghanbarian, B., & Javadpour, F. (2017). Upscaling pore pressure‐dependent gas permeability in shales. Journal of Geophysical Research: Solid Earth, 122(4), 2541-2552. Ghanbarian, B., Torres-Verdin, C., Lake, L. W., & Marder, M. P. (2017). Upscaling gas permeability in tight-gas sandstones. AGU Fall Meeting Abstracts. New Orleans LA. Yassin, M. R., Dehghanpour, H., Wood, J., & Lan, Q. (2016). A theory for relative permeability of unconventional rocks with dual-wettability pore network. SPE Journal, 21(06), 1970-1980.

Cratons are stable parts of the Earth’s continental lithosphere that have remained largely undeformed for several billion years. These consist of crustal granite-greenstone terrains coupled to roots of strong, buoyant cratonic lithospheric mantle that extend up to several hundreds of kms depth. Due to their stability, cratons preserve a record of the tectonics and the thermal evolution of the mantle in the early Earth. These observations suggest that the highly viscous (strong) character of cratons hampered the viability of early Earth tectonics, thereby affecting mantle convection patterns and cooling. In this study, we investigate the controls of stiff cratons on the initiation of subduction and mantle thermal evolution on the early Earth. Using numerical models, we simulate the effects of strong and buoyant cratons on mantle convection. We vary a set of parameters including (i) width and thickness of cratons, and (ii) viscosity ratio between cratonic lithosphere and cratonic crust. We test initial conditions varying the number of cratons, which is unconstrained for early Earth and associated it to mantle cooling rates. Our preliminary results show that the mantle cooling rate decreases with increasing number of cratons. Because mantle cooling rates affect the early Earth transition from a basaltic drip regime to initiation of subduction, we show that the craton coverage on the early Earth controls the time of onset of plate tectonics. Furthermore, we observe that cratons will remain separate or combine depending on the convective cell size, which is function of mantle cooling.

With observational data becoming widely available, researchers struggle to find information enabling assessment for its reliable use. A small first-step toward enabling data quality assessment of observational data is to associate the data with the sensor used to make the observations and to have the sensor description machine-harvestable. In the latest additions to the X-DOMES (Cross-Domain Observational Metadata for Enviromental Sensing) toolset, we have created targeted editors for creating SensorML documents to describe sensor models. The team has adjusted its delivery to enable integration of the X-DOMES content with the GEOCODES (JSON-LD/schema.org) EarthCube project. At our poster-session, we will highlight the new changes and capabilities and demonstrate the use of new X-DOMES tools.

The Chiapanecan Volcanic Arc it is located in the central portion of Chiapas in southern Mexico. This volcanic arc it is merge in a geological complex zone where the interaction of the North American, Caribbean and Cocos plates, near the Motagua-Polochic fault system takes place. The central part of the Chiapanecan Volcanic Arc it is conformed by at least 10 volcanic structures. In this study we focus on five volcanic domes known as La Iglesia, La Mispía, La Lanza, Venustiano Carranza and Santotón. It is described that the volcanic activity in the Chiapanecan Volcanic Arc was effusive accompanied by explosive and phreatomagmatic events. The main lithology varies from andesitic to dacitic rocks with porphyric texture. Both lithologies are mainly composed of euhedral amphibole, pyroxene subhedral plagioclase, as well as subhedral biotite as accessory mineral. It is possible to recognize mafic microgranular enclaves with ovoidal shapes within the andesitic rocks. This work aims to understand the petrological composition, the magmatic activity and its relationship with the subduction of the Cocos plate under the North American plate.

New and recently published U-Pb, muscovite-biotite 40Ar/39Ar, K-feldspar MDD 40Ar/39Ar, zircon and apatite (U-Th)/He, and apatite fission-track data were compiled and inverted for a comprehensive, thermal history of southern Baffin Island, Canada. This work is a contribution to the Geo-mapping for Energy and Minerals (GEM) Baffin Island initiative and Trans-GEM synthesis of the Phanerozoic exhumation history of the Canadian Shield. Southern Baffin Island is comprised of Archean plutonic basement metamorphosed during the Trans-Hudson Orogeny. Monazite U-Pb dating on the Hall Peninsula suggest peak metamorphic conditions were at ca. 1850-1820 Ma and remained at >550ºC ca. 100 My after the thermal peak [1], while 40Ar/39Ar hydrous mineral ages and modeling suggest temperatures remained at >420-450ºC ca. 150-200 My after peak conditions [2]. New apatite U-Pb age populations are in agreement and range from 1674 ± 35 Ma to 1796 ± 75 Ma (2σ), suggesting elevated post-THO temperatures at ~450ºC. During the Meso- to Neoproterozoic the Hall Peninsula region experienced prolonged slow cooling on the order of ≤0.5ºC/My until ca. 1000 Ma when cooling accelerated to ~1ºC/My due to supercontinent Rodinia assembly. Sedimentary sequences place minimum timing constraints on basement rocks being at near-surface conditions in the early Paleozoic. Preliminary results from apatite fission-track data suggest that southwest Baffin (Meta-Incognita and Hall Peninsula) was fully exhumed by Paleozoic time during basement uplift that likely exploited preexisting, regional structures. Nearby Foxe Basin sediments suggest this region of the Canadian Shield was exhumed by the Late Ordovician (ca. 450 Ma) and either remained topographically high, or experienced minor burial during subsequent continental-wide transgression and shallow marine carbonate deposition in the Silurian-Devonian. AFT data from a >1890 Ma volcanic tuff cutting the Paleoproterozoic Hoare Bay Group sediments on the easternmost Cumberland Peninsula record rapid cooling in the Jurassic. The cooling signal recorded along Cumberland Peninsula is likely due to early crustal thinning related to rifting of Greenland from mainland Canada during Pangaea breakup and aligns with a model of rift-flank uplift. AFT models are in agreement with ages of dike swarms in West Greenland given as evidence by [3] for the onset of rift extension. The summarized cooling history of southern Baffin Island suggests post-THO cooling rates of ~1-3ºC/My from ca. 1700-1500 Ma, followed by slow cooling and Mesoproterozoic cooling pulses at ca. 1300 Ma and ca. 1000-950 Ma, likely due to Rodinia assembly. Rocks have been at temperatures <100ºC since ca. 500 Ma. [1] Skipton et al., 2016, J. of Petrology, v.57(8); [2] Skipton et al., 2017, Lithos, v.284; [3] Larsen et al., 2009, J. Geol. Soc., v.166.

We present a 2D model of magma body formation in granitic crust by injection of rhyolitic or basaltic dikes and sills. An elastic analytical solution enables computation of rock displacement in response to magma intrusion. Phase diagrams for magma and host rocks predict melting/crystallization. We combine this model with our zircon crystallization/dissolution software and compute zircon survival histories within individual batches of magma and country rocks. Incremental accumulation of intruded magma generates interconnected magma batches of eruptible melt with melt fractions >50 vol% that form in clusters. The rate of melt production is highly variable in space and time. The volume of eruptible melt strongly depends on the input rates of magma Q and the width W of the injection region of dikes and on eruptions. For example, dikes injection with Q=0.125 m3/s with W=5 km during 100 ka generates ~50 km3 of eruptible melt while no significant melt forms if W=10 km. Injection of basaltic dikes produces more melt for the same flux rate. Frequent and small eruptions led to smaller magma bodies that are located deeper in the system, while systems with rare but voluminous eruption forms large melt. Due to partial melting, most host rock zircons loose significant portion of their old cores and, thus, their average age is reduced. Magmatic zircons in the periphery of the intrusion form very quickly due to rapid dikes cooling while in its central part crystals contain old cores and young rims and can grow during several hundreds of ka.

We examine mid-lower crustal xenoliths erupted in Late Pleistocene to Holocene alkali basalt at San Quintin, Baja California, Mexico to investigate the role of partial melt in deep lithospheric deformation. Using major and trace element mineral chemistry data obtained from LA-ICP-MS and microstructural data obtained from EBSD, we cluster the crustal xenoliths into two groups based on textural and geochemical characteristics: Group (1) largely unfoliated two-pyroxene gabbros with minor amounts of olivine, and Group (2) gabbros with strong compositional foliation and up to 30% modal olivine. We interpret Group 1 xenoliths as representing underplated cumulates from basaltic magmas, whereas petrographic and quantitative microstructural data suggest Group 2 xenoliths record melt infiltration of pre-existing gabbros coeval with deformation, perhaps in a deep crustal shear zone. We propose this shear zone represents a deep lithospheric expression of the active transform plate boundary along the Baja California margin.

Petrographic and major element investigations on carbonates from drill cores recovered during IODP Expedition 357 on the Atlantis Massif (AM) provide information on the genesis of carbonate minerals in the oceanic lithosphere. Textural sequences and mineralogical assemblages reveal three distinct types of carbonate occurrences in ultramafic rocks that are controlled by (i) fluid composition and flow, (ii) temperature of the system, and (iii) the presence of mafic intrusions. The first occurrence of carbonate consists of different generations of calcite that formed syn- to post- serpentinization. These calcites formed at temperatures between 30 and 185°C (based on clumped isotopes) and from a fluid influenced by interaction with mafic intrusions. The second occurrence consists of magnesite, dolomite, calcite and aragonite veins that also formed syn- to post serpentinization. These carbonates formed at temperatures between 4 and 188°C and from fluids with highly variable composition and Mg/Ca ratios, but overall high CO2 and moderate SiO2 concentrations. High FeO (3.3 wt%) and MnO (7.3 wt%) contents indicate high temperatures, high water/rock ratios, and low oxygen fugacity for both carbonate assemblages. The third occurrence consists solely of aragonite veins formed at low-temperatures (5°C) within the uplifted serpentinized peridotites. Chemical data suggest that aragonite precipitated from cold seawater, which underwent little exchange with the basement. Combining these observations, we propose a model that places different carbonate occurrences in a conceptual frame involving mafic intrusions in the peridotites and fluid heterogeneities during progressive exhumation and alteration of the AM.

Ground deformation in the Azores, at the triple junction between the Eurasian, Nubian, and North American plates, has been mapped with continuous GPS (Global Positioning System) geodetic measurements to improve tectonic motion estimates and for understanding volcanic unrest. We compute daily GPS positions, spanning almost 17 years (2000-2017), from 18 continuous GPS stations. The GPS time-series are analyzed by searching for discontinuities and periodic functions. Results show that Flores and Graciosa islands have displacements close to predicted North American and Eurasian plate motions, respectively, while São Miguel, Terceira, São Jorge, Faial and Pico islands have displacements in between predicted Eurasian and Nubian plate motions. The Eurasian-Nubian plate boundary in the Azores behaves as a diffuse ultra-slow oblique spreading center with focused deformation found in the Central Group and Sao Miguel Island. The velocity field is modeled by approximating segments of the Eurasian-Nubian plate boundary with vertical dislocations with right-lateral motion and opening below a locking depth. Best fitting models have deep motion in the range of 2.4-2.7 mm yr-1 on segments directed N(76.5-78.8º)E. Such displacement accounts for more than half predicted Eurasian-Nubian relative plate motion. The modeling results suggest that the locking depth in the Central Group is about 17 km while in São Miguel is about 2 km. We found transient deformation at Fogo volcano, S\~{a}o Miguel Island, due to unrest activity mainly during 2003–2006 and 2011–2012, and local continuous subsidence in Terceira Island, attributed to a deflation source centered on the island.

The characterisation of multiphase flow properties is essential for predicting large-scale fluid behaviour in the subsurface. Insufficient representation of small-scale heterogeneities has been identified as a major gap in conventional reservoir simulation workflows. Capillary heterogeneity has an important impact on small-scale flow and is one of the leading causes of anisotropy and flow rate dependency in relative permeability. We evaluate the workflow developed by Jackson et al. (2018) for use on rocks with complex heterogeneities. The workflow characterises capillary heterogeneity at the millimetre scale. The method is a numerical history match of a coreflood experiment with the 3D saturation distribution as a matching target and the capillary pressure characteristics as a fitting parameter. Coreflood experimental datasets of five rock cores with distinct heterogeneities were analysed: two sandstones and three carbonates. The sandstones exhibit laminar heterogeneities. The carbonates have isotropic heterogeneities at a range of length scales. We found that the success of the workflow is primarily governed by the extent to which heterogeneous structures are resolved in the X-ray imagery. The performance of the characterisation workflow systematically improved with increasing characteristic length scales of heterogeneities. Using the validated models, we investigated the flow rate dependency of the upscaled relative permeability. The findings showed that the isotropic heterogeneity in the carbonate samples resulted in non-monotonic behaviour; initially the relative permeability increased, and then subsequently decreased with increasing flow rate. The work underscores the importance of capturing small-scale heterogeneities in characterising subsurface fluid flows, as well as the challenges in doing so.

Groundwater is critical in sustaining streamflow, especially in mountain catchments, because of its ability to supply baseflow in the absence of precipitation. In water-limited arid and semi-arid mountain environments, the need to characterize groundwater recharge and discharge has grown in tandem with demands to effectively manage current and future water resources. However, studying groundwater is challenging in complex terrain due to limited field measurements. Nearly a decade of monitoring data collection at Gordon Gulch in the Colorado Front Range provides a unique opportunity to study such an environment. The field data is used to parameterize and calibrate a groundwater flow model (MODFLOW-NWT). Model results reveal spatial and temporal patterns in groundwater recharge and discharge to the stream. Groundwater is recharged primarily by one to two recharge events each year, driven by spring snowmelt and rain. The majority of groundwater recharge occurs in upper Gordon Gulch and is stored in saprolite and weathered bedrock. Groundwater is discharged to the stream via long, deep flowpaths sourced from upper Gordon Gulch and short, shallow flowpaths from soil and saprolite in lower Gordon Gulch. Using Gordon Gulch as a case study, this model and data analysis contribute to a larger effort to understand and constrain the mechanisms driving groundwater recharge and groundwater-stream exchanges in semi-arid, montane environments.

Seismic history of the Mosha fault, the most important active fault of Eastern Tehran metropolis, and its relation to the activity of Damavand Volcano, the highest mountain of the Middle-East, is investigated. Historical earthquakes cover the three segments of the Mosha fault by three 6.5

Most of Earth’s volcanic eruptions occur underwater, and these submarine eruptions can significantly impact large-scale earth systems. In this study, we develop a new semi-automated analysis framework to detect submarine eruptions through the supervised classification of satellite images on Google Earth Engine (GEE). We present a case study from the Rabaul caldera region in Papua New Guinea and find a large number of new unreported pumice rafts (in ~16% of images from 2017–present). After analysis of the spatial pattern of raft sightings and ancillary observations, we interpret that these rafts are not the result of a new eruption. Instead, we posit that the observed rafts represent remobilization of pumice clasts from previous historical eruptions. This novel process of raft remobilization may be common at near-shore/partially submarine caldera systems (e.g., Rabaul, Krakatau) and has significant implications for new submarine eruption detection, volcanic stratigraphy, and biological dispersal by rafts.

Krypton-81 dating provides new insights into the timing, mechanisms, and extent of meteoric flushing versus retention of saline fluids in the subsurface in response to changes in geologic and/or climatic forcings over 50 ka to 1.2 Ma year timescales. Remnant Paleozoic seawater-derived brines (2-2.5 km depth) associated with evaporites in the Paradox Basin, Colorado Plateau, are beyond the 81Kr dating range (>1.2 Ma) and have likely been preserved due to negative fluid buoyancy and low permeability. 81Kr dating of formation waters above the evaporites indicates topographically-driven meteoric recharge (0.03-0.8 Ma) and salt dissolution since the Late Pleistocene. Formation waters below the evaporites, in basal aquifers, contain relatively young meteoric water components (0.4-1.1 Ma based on 81Kr) that partially flushed remnant brines and dissolved evaporites. We demonstrate that recent, rapid denudation of the Colorado Plateau (<4-10 Ma) activated deep, basinal-scale flow systems as recorded in 81Kr groundwater age distributions.

The Cameroon Volcanic Line (CVL) is a linear feature of volcanism that begins off the western coast of Africa with several islands and continues on shore through Cameroon further into the African continent. Equatorial Guinea’s Bioko Island is the largest and last of the CVL volcanic islands. It is home to three shield volcanoes: Pico de Basile, Pico Biao, and Gran Caldera de Luba. Eruptive history is only known for Pico de Basile which erupted within the past 100 years, and steam vents were observed as recently as 2012. There is no permanent seismic monitoring; the closest seismic stations are in Cameroon and have not reported data since 2015. The CVL is of scientific interest and has been studied by several groups. Most geophysical studies focus on the area around Mt. Cameroon, the most active volcano in the system. A network of seismic stations was installed across the entire country from 2005-2007. There has been no successful geophysical surveys of the island portion of the line. In Nov-2017 Drexel University, supported by the Bioko Biodiversity Protection Program (BBPP) and the Universidad Nacional de Guinea Ecuatorial (UNGE), installed 4 broadband seismometers on Bioko. Two stations were installed in March of 2019.Preliminary earthquake detection and location was completed with an automated STA/LTA algorithm. Initial locations use the global IASP91 model and events were relocated with a local model. Events cluster in two areas: those near Bioko Island and those near Cameroon. Between 12-Dec-2017 and 17-Feb-2018, 77 events were recorded. Local magnitudes range between 0.16and 2.61. Of these events, 49 are located near Cameroon and 28 are near Bioko. Most of the depths are upper to mid-crust. Analysis of the entire data set yields 458 events with 367 near Bioko Island and 91 near Cameroon. The range in local magnitude is -0.28 – 3.86. Our preliminary results show seismicity associated with Bioko Island as well as Cameroon. Locations match well with events recorded by the regional network previously installed in Cameroon. In addition, the rate of seismicity recorded from2017-2019 is comparable to what was observed from the Cameroon network when distance is taken into account. Data has been retrieved in Feb-2018, Nov-2018, and Mar-2019. The next service was scheduled Mar-2020 but the trip was canceled due to travel restrictions.

Notwithstanding the large number of studies on bedforms such as dunes and antidunes, performing quantitative predictions of bedform type and geometry remains an open problem. Here we present the results of laboratory experiments specifically designed to study how sediment supply and caliber may impact equilibrium bedform type and geometry in the upper regime. Experiments were performed in a sediment feed flume with flow rates varying between 5 l/s and 30 l/s, sand supply rates varying between 0.6 kg/min and 20 kg/min, uniform and non-uniform sediment grain sizes with geometric mean diameter varying between 0.22 mm and 0.87 mm. The experimental data and the comparison with datasets available in the literature revealed that the ratio of the volume transport of sediment to the volume transport of water Qs/Qw plays a prime control on the equilibrium bed configuration. The equilibrium bed configuration transitions from washed out dunes (lower regime), to downstream migrating antidunes (upper regime) for Qs/Qw between 0.0003 and 0.0007. For values of Qs/Qw greater than those typical of downstream migrating antidunes, the bedform wavelength increases with Qs/Qw. At these high values of Qs/Qw equilibrium bed configurations with fine sand are characterized by upstream migrating antidunes or cyclic steps, and significant suspended load. In experiments with coarse sand, equilibrium is characterized by plane bed with bedload transport in sheet flow mode. Standing waves form at the transition between downstream migrating antidunes and bed configurations with upstream migrating bedforms.

The multiscale analysis of fracture patterns helps to define the geometric scaling laws and the genetic relationships correlating outcrop- and regional-scale structures in a fracture network. Here we present the results of the multiscale analysis of the geometrical and spatial organization properties of the fracture network affecting the Rolvsnes granodiorite of the crystalline basement of southwestern Norway (Bømlo island). The fracture network shows a spatial distribution described by a fractal dimension D ≈ 1.51, with fracture lengths distributed following a power-law scaling law (exponent α = -1.95). However, orientation-dependent analyses show that the identified fracture sets vary their relative abundance and spatial organization with scale, defining a hierarchical network. Fracture length, density, and intensity of each set vary following power-law scaling laws characterized by their own exponents. Comparing the results from each set with those generated from the entire network, we discuss how the obtained scaling laws improve the accuracy of resolving sub-seismic-resolution scale structures, which steer the local-scale permeability of fractured reservoirs. As documented in the field, the identified fracture sets affect the fractured basement permeability differently. Thus, results of multiscale, orientation-dependent statistical analyses, integrated with field analyses of fracture lineaments, can effectively improve the detail and accuracy of permeability prediction of fractured reservoirs. Our results show also how regional geology and analytical biases affect the results of multiscale analyses and how they must be critically assessed before extrapolating the conclusions to any other similar case study of fractured unconventional geofluids reservoirs.